Problem
In a one-dimensional flow field, the velocity at a point may be given in the Eulerian system by u=x+2t. Determine the displacement of a fluid particle whose initial position is x0 at initial time to in the Lagrangian system.
Solution
Given u=x+2t
gives on integration

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(A) |
where, c is the constant of integration. C can be found by initial conditions-
For 
Therefore,

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(B) |
Putting value of c from (B) into (A)
This equation represents the Lagrangian version of the fluid particle having the identity at 
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